A synthesis of fluorinated pyrazolcarbaldehydes was described in patent WO 2011/061205. Secondary benzylic amines can be prepared as described in patent WO 2012/059585.
The direct oxidative coupling of aromatic aldehydes and secondary benzylic amines to the corresponding amide is described to some extent in literature. The group of Chen reported the oxidative amidation of various aldehydes with primary and secondary amine hydrochlorides in presence of base, an iron or copper catalyst and tert-Butylhydroperoxide as oxidant (J. Org. Chem. 2012, 77, 8007-8015; Adv. Synth. Catal. 2012, 354, 1407-1412). Pevarello et al. reported one example of oxidative coupling of an imidazothiadiazole carbaldehyde with N-methylbenzylamine in presence of tert-butylhydroperoxide in 29% yield (WO 2009/040552).
However, the oxidative coupling of pyrazolcarbaldehydes, let alone fluorinated pyrazolcarbaldehydes with secondary benzylic amines is not known in literature. In addition, most of the literature procedures for oxidative coupling of aldehyde with amines describe the use of excess aldehyde or amine, which decreases the economic efficiency of the reaction considerably.